Diesel fuel



I Patented a. 31, 1939 UNITED STATES 2,178,327 DIES-EL FUEL Ernest Frank Pevere, Beacon,

and Wilfred N.

Meyer, Newburgh, N. Y., assignors to The Texas Company, New York, N. Y., a corporation of Delaware No Drawing. Application June 26, 1936, Serial No. 87,466.

2 Claims. (Cl. 44-9) This invention relates to improvements in fuels for internal combustion engines of the Diesel or semi-Diesel type and has to do particularly with a combustion primer or accelerator for addition 5 to the fuel to improve the ignition characteristics of the fuel.

In the Diesel type of engine, ignition is effected by compression of air in the engine cylinder and it is desirable for smooth engine operation that there be as short a time lag as possible between the entrance of the first portion of the fuel into the engine cylinder and its auto-ignition. One method of reducing the time lag is to lower the minimum compression ratio necessary for autoignition and this may be done by'the introduction into the fuel, prior to ignition in the engine, of a primer or ignition accelerator. It is an object of the present invention to provide an improved primer which may be added to the fuel in suflicient amount to reduce this time lag.

The primers which are contemplated to be added to a Diesel fuel, in accordance with the present invention, are peroxides of fatty acid anhydrides. We have found that the peroxides of the lower fatty acid anhydrides may be used successfully and we prefer to use peroxides of acid anhydridesv of fatty acids having less than 5 carbon atoms; for example, diacetyl peroxide, dipropionyl peroxide and dibutyryl peroxide. .Of

this class, dipropionyl peroxide has been found to be most effective.

The following examples will fully illustrate the invention:

SSESSSZ The above tests were made on a standard Diesel test engine by measuring the ignition delay. The

data are recorded as a matter of convenience in cetane numbers which designate the percentage by volume of cetane in a mixture of cetane and alpha-methylnaphthylene, which is required to give the same ignition lag to the treated fuel as that of the fuel used as a control.

The amount of the primer added to the fuel may vary from that'given'in the above tests. In general, about 1 to 5% is sumcient and we prefer to use around 3 to 4% although greater amounts than 5% may be used, if desired.

While we have described the invention as applied to the use of the peroxides of the normal fatty acid anhydrides, it is to be understood that the scope of the invention is intended to include various isomers, and substituted derivatives of the fatty acid anhydrides specified.

The primers of the present invention have the advantage that they are easily prepared and have a relatively high. solubility with the oil. They are also safe to handle and efficient for the purpose intended. I

Obviously many modifications and variations of the invention, as her'einbefore set forth, may be made without departing from the spirit and scope thereof, and only such limitations should be imposed as are indicated in the appended claims.

I We claim:

1. The method of improving the ignition characteristics of a Diesel fuel, which comprises adding to the fuel a small amount of dipropionyl peroxide.

- 2. A Diesel fuel containing dipropionyl peroxide in sumcient amount to accelerate ignition.

ERNEST FRANK PEVERE. WILFRED N. MEYER. 

